Effects of a mindfulness-based intervention and a health self-management programme on psychological well-being in older adults with subjective cognitive decline: Secondary analyses from the SCD-Well randomised clinical trial

Objectives Older adults with subjective cognitive decline (SCD) recruited from memory clinics have an increased risk of developing dementia and regularly experience reduced psychological well-being related to memory concerns and fear of dementia. Research on improving well-being in SCD is limited and lacks non-pharmacological approaches. We investigated whether mindfulness-based and health education interventions can enhance well-being in SCD. Methods The SCD-Well trial (ClinicalTrials.gov: NCT03005652) randomised 147 older adults with SCD to an 8-week caring mindfulness-based approach for seniors (CMBAS) or an active comparator (health self-management programme [HSMP]). Well-being was assessed at baseline, post-intervention, and 6-month post-randomisation using the Psychological Well-being Scale (PWBS), the World Health Organisation’s Quality of Life (QoL) Assessment psychological subscale, and composites capturing meditation-based well-being dimensions of awareness, connection, and insight. Mixed effects models were used to assess between- and within-group differences in change. Results CMBAS was superior to HSMP on changes in connection at post-intervention. Within both groups, PWBS total scores, psychological QoL, and composite scores did not increase. Exploratory analyses indicated increases in PWBS autonomy at post-intervention in both groups. Conclusion Two non-pharmacological interventions were associated with only limited effects on psychological well-being in SCD. Longer intervention studies with waitlist/retest control groups are needed to assess if our findings reflect intervention brevity and/or minimal base rate changes in well-being.


Supporting Information
Table S1 Descriptions of the self-report measures included in the meditation-based well-being composites The Compassionate Love Scale (CLS; stranger-humanity version) 1 was used to measure compassion for others.Compassion can be conceptualised as a complex response to suffering -entailing affective, behavioural, and cognitive aspects -that, importantly, includes the intention to reduce suffering.The CLS comprises 21 items with a 7-point Likert scale anchored at 1 (not at all true of me) and 7 (very true of me).Total scales scores are computed by averaging the 21 item scores.Higher total scores reflect higher levels of compassion for others.The CLS has shown high levels of internal consistency (Cronbach's alpha = 0.95) 1 ; however, a recent evaluation of the CLS recommended the use of a shorter 7-item version (i.e., COS-7) 2 .
The Drexel Defusion Scale (DDS) 3 was used to measure levels of defusion, the capacity to psychologically distance oneself from subjective experiences including body sensations, thoughts, emotions and perceptions in general.To be in a state of defusion implies that the seemingly inherent reality commonly assigned to subjective experiences is, to a certain degree, softened, thus making other ways of relating to experience more accessible (e.g.seeing sensations and thoughts as mere phenomenological events or as "just a perception").The DDS comprises 10 items with a 6-point Likert scale ranging from 0 (not at all) to 5 (very much).Total scores are derived by summing the 10 item scores.Higher total scores reflect a greater ability to defuse from subjective experience.The DDS has displayed good psychometric properties including adequate levels of internal consistency (Cronbach's alpha = 0.95) 3 .
The 39-item Five Facet Mindfulness Questionnaire (FFMQ-39) 4 was used to measure five trait-like facets of mindfulness, namely observing (noticing experiences), describing (labelling experiences), acting with awareness (attending to activities non-mechanically), non-judging (non-evaluative stance towards experiences), and non-reactivity (allowing experiences).The FFMQ-39 comprises one 7-item scale (nonreactivity) and four 8-item scales using a 5-point Likert scale anchored at 1 (never or very rarely true) and 5 (very often or always true).After reverse scoring some items, the subscale scores are derived by summing their respective item scores.Higher subscale scores are indicative of a greater tendency to display the mindfulness facets in daily life.The FFMQ subscales have demonstrated adequate psychometric properties including good internal consistency (Cronbach's alpha ranging from 0.75 to 0.91) [4][5][6] .
The Multidimensional Assessment of Interoceptive Awareness (MAIA) 7 questionnaire was used to measure eight state-trait facets of interoceptive awareness, which describe the nervous system's ability to sense, interpret, and integrate signals produced within the body.The 32-item MAIA comprises eight subscales with a 6-point Likert scale anchored at 0 (never) and 5 (always): noticing (awareness of body sensations; 4 items), not-distracting (not ignoring uncomfortable sensations; 6 items), not-worrying (not distressed by uncomfortable sensations; 5 items), attention regulation (sustaining and controlling attention on sensations; 7 items), emotional awareness (awareness of connection between sensations and emotions; 5 items), selfregulation (regulating distress by attention to sensations; 4 items), body listening (listening to the body for insight; 3 items), and trusting (experiencing the body as safe; 3 items).After reverse scoring some items, subscale scores are computed by averaging their respective item scores.Higher subscale scores are indicative of greater interoceptive awareness accessible to self-report.The MAIA subscales have displayed satisfactory to good levels of internal consistency (Cronbach's alpha ranging from 0.64 to 0.83) 7 .

Table S2
Results from exploratory mixed effects models assessing differential change in PWBS dimensions Only participants who provided data at all three time points were included in the analyses.All analyses were adjusted for baseline scores of the outcome.PWBS = Psychological Well-being Scale; SCD = subjective cognitive decline; CI = confidence interval; CMBAS = Caring Mindfulness-based Approach for Seniors; HSMP = Health Self-Management Programme.

Table S3
Exploratory moderator analyses using linear regression models to predict change in well-being outcomes from pre-(V1) to post-intervention (V2) Note.All estimates are accompanied by their 95% confidence intervals.Estimates in bold were associated with p < 0.05.PWBS = Psychological Well-being Scale; QoL = quality of life; CMBAS = Caring Mindfulness-based Approach for Seniors; HSMP = Health Self-Management Programme.